The present invention relates to a sealing terminal and more particularly to a sealing terminal used for a heater having a heating element sealed in a quartz member.
In a process of semiconductor manufacturing, a silicon wafer or the like is subjected to various heat treatments.
Such heat treatments require not only strict temperature control but also a clean atmosphere which is free from particles including fine dusts.
For this purpose, the heater for such heat treatments is required to show uniform heating performance and superior temperature rising and decreasing control capabilities as well as non-emission of polluting matters such as particles.
As one example of the heater for manufacturing semiconductors, there is known a type in which a heating element is sealed in a support member of quartz glass or the like together with a non-oxidizing gas.
The inventors once developed a superior heater for subjecting semiconductors to heat treatments; that is, fine carbon mono filaments bound into a plurality of carbon fiber bundles, which are woven into a carbon wire heating element which in turn is sealed in a quartz glass support member together with a non-oxidizing gas. Said heater is already proposed in Japanese Patent Application H10-254513.
Said carbon wire heating element has such a smaller heat capacity than metallic counterparts that it shows less temperature fluctuation as well as an excellent high temperature resistance in a non-oxidizing atmosphere.
Moreover, since a plurality of fine carbon mono filaments are woven in the manufacture of said carbon wire heating element, it has a remarkable flexibility as compared with a heating element of solid carbon member such that it has an advantage in term of structural variety and workability.
Therefore, said heating element sealed in a heat resistant clean support member of high purity quartz glass or the like together with a non-oxidizing gas will not produce particles and is most suitable as a heater for the semi-conductor manufacturing as stated in the foregoing.
In this connection, the heater which uses the carbon wire element as a heating element requires a terminal device for connection between terminal wires composed of carbon heater bundles and metal wires. The inventors proposed some terminal devices in the above mentioned earlier application.
With reference to FIGS. 7 and 8, the outline of such heaters and terminal devices proposed in said earlier application will be explained.
A carbon heater 50 has substantially an integral structure prepared by sealing a pair of heater members 51 (carbon wire heating element) in a plate-like quartz glass support member 52.
Although not shown, said plate-like quartz glass support member 52 is formed with spaces within which heater elements 51 are accommodated.
Said heater element 51 is in contact with said spaces by way of the carbon fibers having a fluffed surface.
Further, the heater element 51 has its end substantially drawn perpendicularly to a heater face 52a and is connected to a molybdenum (Mo) terminal line 54 by way of a carbon terminal 53 and a connector 58.
Further, said molybdenum (Mo) terminal line 54 is connected to a pair of molybdenum (Mo) terminal line 57 for outside connection by way of a plate-shaped molybdenum (Mo) foil 56.
In this connection, the molybdenum (Mo) foil 56 is pinch sealed by a quartz glass tube 55 together with the respective ends of said molybdenum terminal lines 54 and a pair of such external connection lines 57.
Further, said members are arranged in a glass tube 55 to constitute a sealing terminal.
Now then, said sealing terminal is required to have less electrical resistance to prevent sparks from being generated such that it is possible to supply power to the carbon heating element.
Said terminal structure will suffice the above requirements.
However, said sealing terminal is structured in such a way that the carbon terminal 53 is connected to the molybdenum (Mo) terminal line 54 and the external connection lines 57 by way of the connectors 58 to make the structure complicated and assembly thereof difficult.
Further, a compact sealing terminal is desired considering various devices to be arranged around near the heater.